Nuclear Physics B (Jun 2020)

TMD soft function from large-momentum effective theory

  • Xiangdong Ji,
  • Yizhuang Liu,
  • Yu-Sheng Liu

Journal volume & issue
Vol. 955
p. 115054

Abstract

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We study Euclidean formulations of the transverse-momentum-dependent (TMD) soft function, which is a cross section for soft gluon radiations involving color charges moving in two conjugate lightcone directions in quantum chromodynamics. We show it is related to a special form factor of a pair of color sources traveling with nearly-lightlike velocities, which can be matched to TMD physical observables in semi-inclusive deep-inelastic scattering and Drell-Yan process in the framework of large momentum effective theory. It can also be extracted by combining a large-momentum form factor of light meson and its leading TMD wave function. These formulations are useful for initiating nonperturbative calculations of this useful quantity.